Generally, railroad tracks include a pair of parallel rails coupled to a series of laterally extending ties (or sleepers). Ties may be made from concrete or wood. Each tie is coupled to the rails by metal tie plates and/or spring clips. The ties are disposed on a ballast bed. The ballast may be a hard particulate material, such as gravel. The ballast filled space between the ties is called a crib.
Although appearing rigid, rails are flexible members that can bend and distort, for example under the load of trains passing over. The ballast acts like a cushion absorbing some of the shock. Ballast can also help keep the rail level and allow moisture and rain water to drain away.
During installation and maintenance, ballast may be “tamped” to maintain proper position of the ties. Tamping involves agitating the ballast to allow the particles to re-position, and compact it under the tie.
A tamping device includes one or more workheads mounted on a motorized vehicle that travels on the rails. A workhead may include a pair of elongated, vertically extending tools structured to move together vertically and horizontally in a pincer-like motion. The workhead has two sets of tools spaced so that each tool may be disposed on opposite lateral sides of a rail. The workhead may further include a vibration device configured to rapidly vibrate the tools.
A tamping vehicle typically carries at least one operator. The vehicle accelerates under its own power to the ties requiring work. As it approaches the tie, it slows down, then stops at a tie and performs the required tamping work, and moves to the next tie to repeat the cycle. Tamping work may involve agitating and compacting the ballast through the vertical movement and vibration of the workhead. The constant movement and vibration of the tamping device may cause discomfort to operators sitting in tamping vehicles for extended periods of time.